Search results for "lectrolyte"

Separation of aminoalkanephosphonic acid enantiomers by indirect UV detection capillary electrophoresis with application of cyclodextrins.

2003

Indirect UV detection capillary electrophoresis (CE) was used for the separation of aminoalkanephosphonic acid (AP) enantiomers by applying commercially available cyclodextrins as chiral discriminators. The results show that the separation of the enantiomers depends on pH of the background electrolyte, the molar ratio of cyclodextrin to aminophosphonic acid, and on the type of the applied chiral selector. Optimization of process conditions allowed enantiomeric baseline separation or partial separation of 12 out of 14 alpha-aminophosphonic acids studied. This type of CE might therefore be successfully used for routine determination of enantiomeric purity of aminophosphonic acids.

Effect of ammonium hydroxide addition in the anodizing electrolyte on the electronic properties of anodic oxides on Niobium

2010

Studio di materiali avanzati per celle a combustibile ad ossidi solidi: influenza dei droganti e delle tecniche di sintesi sulle proprietà di anodi e…

2014

Today fuel cell (FC) technology is envisaged as a strategic alternative for providing clean energy through the exploitation of renewable sources; FC research is substantially funded by governments as a mean to meet the global market demand of zero environmental impact. Due to the high level of efficiency, FC devices are already able to compete with the existing power generation technologies and, in particular, solid oxide fuel cells (SOFCs) plants for stationary application constitute one the most efficient way to produce electric power and heat. Nowadays, the main challenges for SOFC research activity are: i) improving costs and durability, by reducing the operating temperature from ∼1000°…

Bi2Se3 Nanostructured Thin Films as Perspective Anodes for Aqueous Rechargeable Lithium-Ion Batteries

2022

This research was funded by the European Regional Development Fund Project (ERDF) No. 1.1.1.1/19/A/139. Y.R. acknowledges the support of post-doctoral ERDF project No. 1.1.1.2/VIAA/4/20/694. V.L. also acknowledges the support of “Strengthening of the capacity of doctoral studies at the University of Latvia within the framework of the new doctoral model”, identification No. 8.2.2.0/20/I/006. A.S. acknowledges the support from the Institute of Solid State Physics, University of Latvia, which, as the Center of Excellence, has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.

Electrochemical and Spectroelectrochemical Properties of Free-Base Pyridyl- and N -Alkyl-4-Pyridylporphyrins in Nonaqueous Media

2015

International audience; Twelve structurally related pyridyl and meso-N-methylpyridylporphyrin derivatives are investigated electrochemically in different nonaqueous media. The UV/Vis spectrum of each newly investigated porphyrin was measured before and after electro-reduction and, based on this data, the site of electron transfer is proposed. An interaction occurs between the meso-pyridyl or meso-N-alkyl-4-pyridyl substituents and the porphyrin p-ring system, the magnitude of which depends upon the number of linked pyridyl or N-alkyl-4-pyridyl groups in the compound, the solvent, the supporting electrolyte, and/or other anions added to the solution.

Electrochemical ecology: VIMP monitoring of plant defense against external stressors

2015

The use of the voltammetry of immobilized particles (VIMP) approach, by means of the voltammetric response of microparticulate films from ethanolic leaf extracts in contact with aqueous electrolytes and direct contact probe leaf voltammetry, to monitor the defense of plants against external stressors is described. This approach is applied to study the chemical communication between plants of Peperomia obtusifolia A. Dietr. submitted to herbivory by the beetle Monoplatus sp.

Protection of living yeast cells by micro-organized shells of natural polyelectrolytes

2015

International audience; Saccharomyces cerevisiae, a eukaryotic model organism, plays a key role in the oxidative stability of fermented products. In order to protect cells against environmental stresses, we report a method of modifying the cell surface architecture while maintaining the internal working properties of the system. The objective was to encapsulate living yeast cells in micro-organized polyelectrolyte shells using layer-by-layer (LbL) assembly. For the first time, the natural polyelectrolytes, β-lactoglobulin and sodium alginate, were alternately deposited on the surface of S. cerevisiae. Transmission electron microscopy coupled with immune-cytochemistry and scanning electron m…

Uranyl sorption onto birnessite: A surface complexation modeling and EXAFS study

2014

This work investigates the mechanism of the uranyl interaction with birnessite, one of the most common layer-type MnO2 mineral at the Earth's surface, by coupling macroscopic (surface complexation experiments) and microscopic (EXAFS measurements) approaches. The sorption of uranyl on synthetic hexagonal birnessite, the low-pH birnessite form, was studied under various conditions of pH (3–6), electrolyte backgrounds (0.1 M NaClO4, NaNO3 and Na2CO3), and solid/liquid ratios (from 0.27 to 4.5 g/L). Sorption isotherms exhibit a complex form indicative of at least two types of sorption sites. EXAFS data reveal the presence of two equatorial O shells at ca. 2.32 Å and 2.46 Å for all the samples, …

Electrochemical C−H Functionalization of (Hetero)Arenes—Optimized by DoE

2020

Abstract A novel approach towards the activation of different arenes and purines including caffeine and theophylline is presented. The simple, safe and scalable electrochemical synthesis of 1,1,1,3,3,3‐hexafluoroisopropanol (HFIP) aryl ethers was conducted using an easy electrolysis setup with boron‐doped diamond (BDD) electrodes. Good yields up to 59 % were achieved. Triethylamine was used as a base as it forms a highly conductive media with HFIP, making additional supporting electrolytes superfluous. The synthesis was optimized using Design of Experiment (DoE) techniques giving a detailed insight to the significance of the reaction parameters. The mechanism was investigated by cyclic volt…

Effect of pressure on the electrochemical generation of hydrogen peroxide in undivided cells on carbon felt electrodes

2017

The electrochemical generation of H2O2can be performed in aqueous solutions by cathodic reduction at carbonaceous cathodes of oxygen coming from air. The performances of the process in terms of concentration of H2O2and current efficiency (CE) are limited by the low solubility of oxygen in water at atmospheric pressure. However, the solubility of oxygen can be increased upon enhancing the air pressure. The effect of pressure on the electrochemical generation of hydrogen peroxide was studied in undivided cells changing the pressure from 0 to 30 relative bar and the current density from 1 to 100 mA cm−2. Simple carbon felt and compact graphite cathodes were first used. A dramatic effect of…